unlock deceased child's iphone and icloud account

For information about how to request access to a deceased family member's Apple account data, and possibly their equipment, click here --> How to request access to a deceased family member's Apple account - Apple Support

"While we may also be able to help remove Activation Lock from devices that use your loved one’s original Apple ID, their iPhone, iPod, and iPad will need to be restored to factory settings before they can be used with another Apple ID. Please note that devices locked with a passcode are protected by passcode encryption, and Apple can't help remove the passcode lock without erasing the device.

I have never used the service, and the steps required may also depend upon your country. Apple does not say how quickly the reset process takes even if you do already have all the required documentation. You can try contacting Apple.

Refer to this document for ways to contact Apple --> Choose your country or region - Official Apple Support

Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service by telephone --> Contact Apple for support and service - Apple Support

Hello ~ In addition to * Limnos’* helpful information please accept my condolences for the loss of your son.

~Katana-San~